Can Women Take Nitric Oxide Supplements?

Women can take nitric oxide supplements, and research increasingly suggests they may benefit from them in ways that differ from men. Nitric oxide is a molecule the body produces naturally to relax blood vessels, regulate blood flow, and support immune function. The supplements marketed as “nitric oxide boosters” don’t contain nitric oxide itself but instead supply precursor ingredients like L-arginine, L-citrulline, or dietary nitrate (often from beetroot) that the body converts into nitric oxide. What makes the picture interesting for women is that estrogen plays a direct role in nitric oxide production, creating a biological backdrop that shifts across the menstrual cycle, pregnancy, and menopause.

Why Estrogen Makes This a Different Conversation for Women

Estrogen doesn’t just regulate reproductive function. It actively increases the production and activation of the enzyme responsible for making nitric oxide in blood vessel walls, called endothelial nitric oxide synthase (eNOS). This happens through multiple pathways: estrogen boosts eNOS gene activity and also rapidly activates the enzyme through receptors located directly in endothelial cells.¹ In rat models, estrogen treatment produced higher levels of both eNOS protein and nitric oxide synthase activity in cerebral blood vessels, and blocking estrogen receptors completely prevented the effect.²

This estrogen-nitric oxide link shows up clearly when researchers compare blood vessel behavior between sexes. In one study using isolated arterioles, vessels from female rats dilated significantly more in response to blood flow than those from males, and removing the ovaries reduced that dilation to male-like levels. Replacing estrogen restored it.³ In healthy women, the abundance of estrogen receptor alpha in vascular cells was positively correlated with eNOS expression and activation, providing a direct molecular link between estrogen status and nitric oxide capacity.⁴

The practical takeaway is that a woman’s baseline nitric oxide production is tied to her hormonal status. When estrogen is high, the body is already producing more nitric oxide on its own. When estrogen drops, as it does during certain phases of the menstrual cycle and especially during menopause, the body’s natural NO-producing machinery slows down. This creates windows where supplementation could, at least in theory, fill a gap that doesn’t exist in the same way for men.

What Happens After Menopause

The decline in endothelial function across the menopause transition is well documented and directly tied to falling estrogen levels. In a study of 87 healthy women spanning premenopause through postmenopause, blood vessel dilation (measured by flow-mediated dilation of the brachial artery) decreased progressively across stages. Suppressing ovarian hormones experimentally worsened dilation in premenopausal and perimenopausal women but had no further effect in postmenopausal women, whose function was already reduced. Adding estrogen back restored dilation in the earlier groups. Infusing vitamin C, an antioxidant, improved blood vessel function in the late perimenopausal and postmenopausal women but not in premenopausal women, pointing to oxidative stress as a driver of the decline.⁵

This is where nitric oxide supplements have shown some of their most promising results in women. In postmenopausal women, a single dose of nitrate-rich beetroot juice reduced brachial systolic blood pressure by about 5 mmHg and central (aortic) systolic blood pressure by about 6 mmHg compared to placebo.⁶ A separate trial in postmenopausal women with high blood pressure found that nitrate-rich beetroot juice produced a drop in systolic blood pressure of roughly 9 mmHg during post-exercise recovery compared to placebo.⁷

A systematic review of L-citrulline supplementation in postmenopausal women, covering 12 randomized controlled trials and 360 participants, found that most studies reported reductions in systolic blood pressure and mean arterial pressure. Results on arterial stiffness were mixed, but two of four studies examining blood vessel function found significant improvements.⁸ In hypertensive postmenopausal women specifically, L-citrulline supplementation significantly improved forearm blood flow and muscle oxygenation during exercise, suggesting that the vascular effects translate into functional gains during physical activity.⁹

Exercise and Athletic Performance

The performance literature for women is smaller and more mixed than for men, partly because exercise science has historically under-recruited female participants. Still, the studies that do exist paint an interesting picture. In a double-blind crossover trial of female athletes, beetroot juice supplementation improved countermovement jump height, increased mean and peak power in back squats by about 6 to 7 percent at a submaximal load, and improved muscular endurance compared to placebo.¹⁰ Those are meaningful improvements, particularly in a population that is already trained.

Not all studies are as positive. A trial of well-trained female ringette players found that acute beetroot juice supplementation did not reduce oxygen consumption during cycling at moderate and high intensities, though it did significantly lower ratings of perceived exertion at both levels. A few participants did show individual oxygen-cost improvements, but the group-level effect was not there.¹¹ And a study testing an 8-gram dose of L-citrulline found no improvements in isometric force, muscular endurance, or muscle oxygenation in recreationally trained men and women.¹²

Citrulline alone may not do much for muscle function in older women either, according to a systematic review that found improvements only when citrulline was combined with resistance training.⁸ The pattern here is consistent with the broader nitric oxide supplement literature: vascular effects (blood pressure, blood flow) tend to be more reliable than direct performance effects, and results depend heavily on the specific supplement, the dose, and the population being studied.

Does the Menstrual Cycle Matter for Timing?

Given the estrogen-nitric oxide connection, a reasonable question is whether NO supplements work better during certain phases of the menstrual cycle. Estrogen is lowest during menstruation and the early follicular phase and peaks around ovulation. Plasma nitric oxide levels do fluctuate somewhat across the cycle: one study found lower levels in the preovulatory phase compared to the midluteal phase.¹³ Researchers have hypothesized that supplementation with nitrate might be more effective when endogenous NO production is low, specifically when estradiol is low.¹⁴

The evidence for this idea, however, is still thin. A recent study specifically examining whether the shift from the early follicular to the late follicular phase affects microvascular function and eNOS protein levels found no significant differences between phases in leg blood flow or in the relevant enzyme levels.¹⁵ The cycle-phase theory is plausible on paper, but as a practical guide for when to take supplements, it’s premature. If you’re a premenopausal woman considering nitric oxide supplementation, consistent daily use is a simpler approach than trying to time it around your cycle.

A Biological Quirk in How Women Process Nitrate

Dietary nitrate, the kind found in beets and leafy greens, doesn’t turn into nitric oxide on its own. Bacteria on the tongue first reduce nitrate to nitrite, and the body then converts nitrite to nitric oxide in the stomach and bloodstream. This oral conversion step turns out to differ between women and men. One study found that women had higher oral bacterial nitrate-reducing activity both at baseline and after nitrate supplementation, contributing to higher circulating nitrite levels.¹⁶ The difference was in bacterial activity, not in the types of bacteria present. Interestingly, a separate study comparing nitrate-reducing bacteria between oral sites found no significant differences between male and female subjects at any given location in the mouth.¹⁷

The implication is that women may convert dietary nitrate to nitric oxide more efficiently, which could mean they need a lower dose to achieve the same effect, or that they benefit more from nitrate-based supplements (like beetroot juice) relative to precursor-based ones (like L-arginine or L-citrulline, which bypass the oral route entirely). This is speculative but worth keeping in mind if you’re choosing between supplement types. It also means that antibacterial mouthwash, which kills the very bacteria responsible for nitrate conversion, could blunt the effect of beetroot-based supplements regardless of sex.

Sexual Health and Nitric Oxide

Nitric oxide plays a role in female sexual arousal that parallels its better-known role in male erectile function. During arousal, clitoral blood flow is controlled by eNOS and nitric oxide.¹⁸ The signaling mechanism is essentially the same: nitric oxide relaxes smooth muscle in genital blood vessels, allowing increased blood flow and engorgement. This has led some clinicians and researchers to explore whether NO-boosting supplements might help with female sexual arousal disorders, though the supplement industry tends to market these products primarily to men.

Clinical trials directly testing NO supplements for female sexual dysfunction are limited, so the connection remains more theoretical than proven at this point. The biological pathway is clear, but whether taking a supplement meaningfully affects sexual response in a real-world context is something the research hasn’t firmly established.

Pregnancy Considerations

Pre-eclampsia, a dangerous pregnancy complication involving high blood pressure and organ damage, is associated with impaired nitric oxide signaling. This has led researchers to test whether NO precursors might help prevent or manage the condition. In one trial, three weeks of L-arginine supplementation in women with pre-eclampsia significantly lowered systolic, diastolic, and mean arterial blood pressure compared to placebo, and the reductions were accompanied by increased markers of nitric oxide production.¹⁹

However, a Cochrane systematic review assessing the broader body of evidence concluded that there is insufficient evidence to draw reliable conclusions about whether nitric oxide donors and precursors prevent pre-eclampsia or its complications.²⁰ Individual trials look promising, but the totality of the evidence isn’t there yet. Pregnant women should not self-supplement with NO boosters for this purpose. Any use during pregnancy should be under direct medical supervision, and the same caution applies to nitric oxide supplements generally since they may interact with other medications.²¹

PCOS and Insulin Resistance

Polycystic ovary syndrome affects an estimated 6 to 12 percent of women of reproductive age and carries increased cardiovascular risk. Research has identified a specific link between nitric oxide levels and insulin resistance in women with PCOS. In these women, higher insulin levels and greater insulin resistance are correlated with lower NO production, independent of body weight.²² A separate analysis found that high fasting insulin roughly doubled the odds of having low NO levels in PCOS patients.²³ Low NO responsiveness and vitamin D deficiency were also associated with reduced insulin sensitivity in a broader cohort of young women, with the relationship being especially pronounced in those with PCOS.²⁴

This doesn’t mean that popping an L-citrulline capsule will fix insulin resistance in PCOS. It means that impaired NO signaling is part of the vascular dysfunction that contributes to PCOS-related cardiovascular risk, and it suggests that strategies to support NO production, whether through diet, exercise, or supplementation, could be worth exploring alongside standard treatments. The research connecting supplementation itself to measurable improvements in PCOS outcomes is still early.

Safety, Interactions, and Practical Guidance

For most healthy women, nitric oxide supplements at standard doses are considered safe. In a study of hypertensive patients (including both men and women), a single dose of an oral NO supplement lowered systolic blood pressure by about 4 mmHg within 20 minutes and by 6 mmHg after an hour, with simultaneous improvements in vascular compliance and endothelial function and no reported serious adverse effects.²⁵ A study of uncontrolled hypertension patients already on antihypertensive medication found that a nutraceutical combination working through nitric oxide pathways reduced blood pressure and improved exercise capacity.²⁶

That last point is also a caution. If you’re already taking blood pressure medication, adding a supplement that further lowers blood pressure can push it too low, causing dizziness, lightheadedness, or fainting. The same applies to vasodilator medications used for other conditions. Nitric oxide supplements may also interfere with anticoagulants and other medications, so talking to a doctor before starting is worthwhile, especially if you have any existing cardiovascular condition or are on multiple prescriptions.²¹

As for choosing between supplement types, the three most common options differ in how they work:

Beetroot juice or nitrate supplements: These supply inorganic nitrate that gets converted to nitrite by oral bacteria and then to nitric oxide in the body. Because women appear to have more active oral nitrate-reducing bacteria, this route may be particularly effective.
L-citrulline: Converted to L-arginine in the kidneys, which then gets used to produce nitric oxide enzymatically. This bypasses the oral bacteria step entirely. Evidence in postmenopausal women shows blood pressure benefits, and some studies show improved blood flow during exercise.
L-arginine: The direct substrate for nitric oxide production, but much of it gets broken down in the gut before reaching the bloodstream. L-citrulline is generally considered a more efficient way to raise arginine levels.

Raynaud’s Phenomenon and Circulation Issues

Raynaud’s phenomenon, where blood vessels in the fingers and toes overreact to cold and constrict dramatically, disproportionately affects women, particularly those with autoimmune conditions like scleroderma. Nitric oxide’s role as a vasodilator makes it a logical therapeutic target. An early clinical study found that intra-arterial infusions of L-arginine and sodium nitroprusside (an NO donor) significantly decreased the occurrence of laboratory-induced Raynaud’s episodes in scleroderma patients.²⁷

More recent work has explored whether oral supplements can achieve similar results. A study of beetroot juice supplementation in people with Raynaud’s found improvements in thumb blood flow, endothelial function, anti-inflammatory markers, and blood pressure.²⁸ However, a more rigorous series of individual N-of-1 trials testing both beetroot juice and L-citrulline found that neither supplement had a significant effect on patient-defined primary outcomes in any individual participant, though beetroot juice did significantly reduce the cumulative duration of attacks.²⁹ The evidence here is mixed enough that NO supplements shouldn’t be considered a reliable treatment for Raynaud’s, but for women who find that cold-triggered episodes affect their daily life, discussing it with a doctor as an adjunct strategy is reasonable.

Skin and Blood Flow

Beyond internal vascular health, nitric oxide also affects skin blood flow, which has implications for skin health and even cosmetic applications. A recent study tested a topical compound (N,N-dimethylglycine sodium salt) that stimulates endothelial nitric oxide release in skin cells. The treatment increased cellular NO production and significantly boosted skin blood flow measured at both shallow and deeper tissue levels, with effects lasting over 90 minutes.³⁰ While this was a topical application rather than an oral supplement, it illustrates the principle: nitric oxide-mediated blood flow improvements can reach the skin.

A trial looking at beetroot extract supplementation in aging women found that six weeks of supplementation during a training program resulted in lower urea levels (suggesting reduced muscle protein breakdown) and lower creatine kinase activity (suggesting better-preserved muscle function) compared to placebo and L-arginine groups. The beetroot group appeared to show benefits more aligned with short-term training adaptations, and the effects were more pronounced in women than in men.³¹ For women interested in preserving muscle function as they age, combining beetroot or nitrate-based supplements with regular resistance training may offer benefits beyond what either approach provides alone, though this is early evidence from small trials.

A pilot study of healthy young African-American women found that beetroot juice increased blood nitric oxide levels, decreased systolic blood pressure at rest and during exercise, and reduced a marker of arterial stiffness during exercise.³² That last finding, the reduction in arterial stiffness during physical activity, matters because it suggests improved delivery of blood to the brain and other organs under stress, not just a resting blood pressure change.